digitrevorder

Syntax

y = digitrevorder(x,r)[y,i] = digitrevorder(x,r)

Description

digitrevorder is useful
for pre-ordering a vector of filter coefficients for use in frequency-domain
filtering algorithms, in which the fft and ifft transforms are computed without
digit-reversed ordering for improved run-time efficiency.

y = digitrevorder(x,r) returns
the input data in digit-reversed order in vector or matrix y.
The digit-reversal is computed using the number system base (radix
base) r, which can be any integer from 2 to 36.
The length of x must be an integer power of r.
If x is a matrix, the digit reversal occurs on
the first dimension of x with size greater than
1. y is the same size as x.

[y,i] = digitrevorder(x,r) returns
the digit-reversed vector or matrix y and the digit-reversed
indices i, such that y = x(i). Recall that MATLAB® matrices use 1-based
indexing, so the first index of y will be 1, not
0.

The following table shows the numbers 0 through 15, the corresponding
digits and the digit-reversed numbers using radix base-4. The corresponding
radix base-2 bits and bit-reversed indices are also shown.